Primary Deep Sclerectomy in Open-Angle Glaucoma: Long-Term Outcomes and Risk Factors for Failure

Purpose: To report long-term outcomes of primary deep sclerectomy (DS) in open-angle glaucoma (OAG) and identify factors influencing surgical failure and postoperative complications. Design: Retrospective cohort study. Participants: Consecutive OAG patients undergoing primary DS with follow-up of 1 year or more. Methods: Three intraocular pressure (IOP) success cutoffs were defined: 18 mmHg or less and 20% reduction, 15 mmHg or less and 25% reduction, and 12 mmHg or less and 30% reduction. Cox multivariable regression analysis investigated factors influencing failure and postoperative complications. Main Outcome Measures: The primary outcome was the success rate of DS according to the defined criteria. Secondary outcomes included IOP over time and factors predictive of failure. Results: Five hundred thirteen eyes of 409 patients with a mean age ± standard deviation (SD) of 70.2 ± 9.8 years and follow-up of 84.1 ± 41.6 months. Mean ± SD IOP decreased from 23.5 ± 7.3 mmHg to 13.3 ± 3.9 mmHg, 12.8 ± 4.3 mmHg, and 12.4 ± 4.3 mmHg at 3, 5, and 7 years, respectively (P < 0.001). Success rates at 3, 5, and 7 years were 66.3% (95% Confidence Interval [CI] 62.2%–70.7%), 57.9% (95% CI 53.4%–62.7%), and 54.0% (95% CI 49.4%–59.1%), respectively, for IOP of 18 mmHg or less; 44.5% (95% CI 40.3%–49.1%), 34.6% (95% CI 30.4%–39.4%), and 29.8% (95% CI 25.6%–34.6%), respectively, for IOP of 15 mmHg or less; and 18.1% (95% CI 15.0%–21.9%), 11.9% (95% CI 9.2%–15.4%), and 10.0% (95% CI 7.5%–13.4%), respectively, for IOP of 12 mmHg or less. For all cutoffs, laser goniopuncture (P < 0.001), needling (P < 0.001), and postoperative antiglaucoma medications (P < 0.001) were associated with increased failure. Intraoperative mitomycin C (MMC) was associated with reduced failure for IOP of 15 mmHg or less (P = 0.006) and IOP of 12 mmHg or less (P = 0.001), whereas higher preoperative IOP (P = 0.001) with increased failure for IOP of 12 mmHg or less. Conclusions: Deep sclerectomy is an effective, long-lasting primary surgical procedure for OAG. Intraoperative MMC enhances survival, whereas higher preoperative IOP and postoperative maneuvers are predictors of increased failure.